Overhead valve internal combustion engines



Dec. 6, 1960 E. R. PAYNE 2,963,010

OVERHEAD VALVE INTERNAL coNBUsTIoN ENGINES Y Filed May 5, 1959 I n ntor@f4-'u K. 7AM s BMM I Home ys United States Patent O 2,963,010 OVERHEADVALVE INTERNAL COMBUSTION ENGINES Eric R. Payne, Northfield, Birmingham,England, assignor to The Austin Motor Company Limited, Birmingham,England Filed May 5, 1959, Ser. No. 811,992

application Great Britain May 30, 1958 1 Claim. (Cl. 123--55) Claimspriority,

This invention relates to overhead valve internal combustion engines ofthe kind in which the cylinder block is formed with cylinder boresinclined at a small angle, alternately one to the left and one to theright, with respect to a vertical plane (hereinafter referred to as thecentre plane) in which the crankshaft axis is disposed, the arrangementbeing such as to enable a compact arrangement of cylinder head and valveoperating mechanism to be obtained.

A. multi-cylinder overhead valve engine of the kind referred to, andaccording to the present invention, is characterised in that the valvesfor the cylinders on opposite sides of the centre plane are operated byrockers which are all pivotally mounted on the same rockershaft which ismounted in bearings on the cylinder head with its axis disposed in thecentre plane, that a camshaft from which said rockers are operated bytappets and push -rods has its axis in said centre plane and is mountedin bearings formed in or carried by the cylinder head at a position lowdown in the latter and in that the pairs of tappets, for actuating theinlet and exhaust valves of the respective cylinders, operate in guidebores in the cylinder head which are inclined, in pairs, alternately toright and left of the centre plane so that the upper ends of the pushrods engage the tails of the rockers which are oppositely disposed onthe rockershaft.

The invention will now be more fully described with reference to and bythe aid of the embodiment shown in the accompanying drawings;in which:

Fig. 1 is a fragmentary end elevation, partly in section, of a fourcylinder overhead valve internal combustion engine of the kind referredto.

Fig. 2 is a plan of the engine shown in Fig. 1, but with the top coverand some parts of the valve gear removed for the sake of clearness.

Referring to the drawings, the engine comprises a cylinder block formedwith cylinder bores 11 tted with liners 12 in which pistons 13 operate,said bores 11 being inclined at a small angle, alternately one to theleft and one to the right, with respect to the centre plane in which thecrankshaft axis is disposed. The cylinder block 10 is surmounted by acylinder head casting 14 which is formed on its otherwise flat undersideor jointing face with recesses 14x which register with the respectivecylinders and afford, jointly with the upper parts of the latter, thecombustion chambers.

The cylinder head casting 14 is also cored out to afford branchedsuction inlet manifolds 15, for the cylinders on opposite sides of thecentre plane, and separate exhaust ducts 16 for the four cylinders,whilst poppet type inlet valves 17 and exhaust valves 1S for thecylinders operate in stem guides 19 which are mounted in guide bores 20in the cylinder head, said guide bores 20 being inclined, in pairs,alternately to right and left of and upwardly toward the centre plane.The valves 17, 18 for the cylin- ICC ders on opposite sides of thecentre plane are operated by rockers 21 which are all mounted on acommon rockershaft 22 which is itself mounted in bearings at 23 on thecylinder head casting 14 with its axis in the said centre plane, saidrockers 21 being oppositely disposed or arranged alternately on therockershaft 22, that is to say the rockers 21 for operating the valves17, 18 on one side of the centre plane alternate with those whichoperate the valves 17, 18 on the other side of the rockershaft 22 (seeparticularly Fig. 2).

A camshaft 23x from which the said rockers 21 are operated by tappets 24and push rods 25 has its axis in the centre plane and is mounted inbearings formed or carried in a cored-out housing 26 formed at aposition low down in the cylinder head casting 14, and the pairs oftappets 24, for actuating through the push rods 25 the valves 17, 18 ofthe respective cylinders, operate in guide bores 27 in the cylinder headcasting 14, which guide bores 27 are inclined, in pairs, alternately toright and left of the centre plane (see Fig. 2) so that the upper endsof the push rods 25 engage the tails of the rockers 21 which areoppositely disposed on the rockershaft 22.

Separate carburetters 28 (see Fig. 1) would be secured one to each sideface of the cylinder head casing to con nect with the branched suctioninlet manifolds leading to the two cylinders on either side, whilstbranches of separate exhaust pipes (not shown), one on either side,would be connected to the separate exhaust ducts 16 from the fourcylinders.

The invention lends itself to a very compact cylinder head, camshaft andvalve gear assembly employing tappets and very short push rods and onlyone rockershaft, which assembly can readily be removed as a unit fromthe cylinder block after disconnecting the camshaft drive from theengine crankshaft.

Having fully described my invention, desire to secure by Letters Patentis:

For use with a V-type multi-cylinder overhead valve engine having acylinder block provided with cylinder bores, a cylinder head having aliat lower face adapted to be secured to the upper face of said block. arockershaft, a plurality of bearings carried by the cylinder head formounting said rocker-shaft with its axis disposed in said center plane,a pair of guide bores for each cylinder bore, said guide bores beingpositioned in the cylinder head on opposite sides of said center planeand being inclined upwardly and inwardly with respect to said flat facetoward said center plane, a valve having a stem positioned in each guidebore, and means for operating said valves comprising a camshaft carriedentirely within said cylinder head and having its axis positioned insaid center plane below said rocker-shaft, rockers carried by saidrocker-shaft, and a plurality of push rods sloping upwardly andoutwardly with respect to said camshaft and operatively connecting thelatter and said rockers.

what I claim and References Cited in the tile of this patent UNITEDSTATES PATENTS

